Effect of Sb doping on the structural, electrical, and optical properties of SnO₂ thin films prepared through spray pyrolysis

Abstract

In this research, antimony-doped tin dioxide (ATO) films were deposited on glass substrates at T = 550 °C through spray pyrolysis. The effects of antimony doping on the structural, optical, and electrical properties of the thin films were investigated. Tin chloride (SnCl₄·5H₂O) and antimony chloride (SbCl₃) were used as a host and a dopant precursor, respectively. X-ray diffraction (XRD) analysis indicated that the undoped SnO₂ thin film exhibited a preferred (211) orientation. As the Sb doping concentration increased, a different preferred (200) orientation was observed. Field emission scanning electron microscopy analysis revealed polyhedron-like grains of the thin films. Atomic force microscopy analysis demonstrated that the minimum and maximum amounts of roughness were within the $\frac{{\left[ {Sb} \right]}}{{\left[ {Sn} \right]}}\%$ molar ratio of 10 and 7.5 at.% concentrations, respectively. As the doping concentration increased, the average grain size initially increased and then decreased; electrical resistance initially decreased and subsequently increased; the carrier concentration and Hall mobility initially increased and then decreased; and Seebeck coefficient decreased. The optical band gap of the thin films ranged from 3.16 to 3.8 eV. Hall effect and thermoelectric studies revealed that the films exhibited an n-type conductivity.